That's sadly true, which sometimes drives academics to focus more effort on publications and see teaching as a "burden" because it takes away from their time that can be spent "creating more value" for their careers. But most of us became academics because we were inspired by great teachers.

Maybe what they meant to say was teaching workload, which is a more neutral way of putting things. But yes, teaching itself is seldom a burden, and is more often the biggest source of joy in academia.

And it's really because the human brain operates more efficiently with dichotomy than it does with continuums. If we understood this more, we could change more behaviours.